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Lock-free ring buffer memory barriers test case   Message List  
Reply | Forward Message #285 of 300 |
Re: [liblf-dev] Lock-free ring buffer memory barriers test case

On Wed, Oct 29, 2008 at 11:37 AM, Bjorn Roche <bjorn@...> wrote:
> Plus, gcc, for example, tends to
> insert memory barriers in places, like at function calls.

I really don't think so. citation?


--
--- james mccartney



Thu Oct 30, 2008 9:10 pm

james_e_mcca...
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Message #285 of 300 |
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Hi, Can any of you advise a good test case that would demonstrate memory barriers are needed in a lock-free ring buffer ? I mean: a piece of code that would...
oja_i_i
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Oct 29, 2008
3:44 am

Many optimizing compilers will make things work, not because they should work, but because optimizers like to remove operations and that tends to make things...
Bjorn Roche
bejayoharen
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Oct 29, 2008
6:37 pm

... Thanks for your answer. Is this the counter example you mention: http://tech.groups.yahoo.com/group/liblf-dev/message/203 ? -- Olivier Guilyardi / Samalyse...
oja_i_i
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Oct 30, 2008
2:12 pm

... Gosh that's hard to read without the tabs! I think that was just a standard ringbuffer, not a proof that memory barriers are needed design. bjorn ... Bjorn...
Bjorn Roche
bejayoharen
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Oct 30, 2008
3:21 pm

... I really don't think so. citation? --...
James McCartney
james_e_mcca...
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Oct 30, 2008
9:20 pm

... I can't find a citation right now, so I could be wrong. If I am wrong, sorry about that. It's obviously not behavior to count on anway, since even if you...
Bjorn Roche
bejayoharen
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Oct 31, 2008
2:34 pm

... Even with -O0? Steve...
Stephen Sinclair
sinclairs828
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Nov 1, 2008
6:17 am

... I've read so many citations, and other theories about ring buffers and memory barriers. But to me they're useless until someone can write a piece of code...
oja_i_i
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Nov 1, 2008
6:17 am

Hello, I just saw this postedon reddit, I'm not sure but I thought it might be relevant to this discussion. ...
Stephen Sinclair
sinclairs828
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Nov 6, 2008
6:57 am

There are two files in the file section of this list. I scanned the emails of this list quickly and I think they both ran fine for many people and failed for...
Bjorn Roche
bejayoharen
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Nov 6, 2008
3:18 pm

I don't think so either. I'd be surprised if gcc inserts any memory barriers. But I do remember reading somewhere that a C optimizer probably won't reorder...
Ross Bencina
ross_bencina
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Nov 1, 2008
6:15 am
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